Social & Preventive Medicine General 5277a70b Requirement of vitamin B12 per day for adults is: A 1 mcg B 3 mcg C 5 mcg D 7 mcg High-Yield Explanation Requirement of vitamin B12 per day Healthy adults 1 mcg Pregnancy 1.2 mcg Lactation 1.5 mcg children 0.2 mcg Ref: Park 22nd edition, page 575.